The present invention relates generally to sports equipment testing and, more particularly, to a system and methods for testing the performance of a striking implement such as a baseball bat or racket in conjunction with a ball or other associated projectile.
There is an outstanding need in professional sports to quantify the performance of the equipment involved, and to provide tools to evaluate the performance of existing devices. At the present time, for example, the evaluation of bats, balls, and so forth, is almost completely dependent on the experience and observations of the players who use such equipment. These observations are supported only by an empirically derived historical database of performance statistics. Other than radar guns to measure ball velocity and video cameras for player viewing, there are no quantitative measures of ball movement (s), bat performance, etc. The need remains, therefore, for an analysis and testing system which may be used to monitor the swing of a striking type sports implement such as a bat as it strikes a ball, and to gather information as to swing speed, projectile delivery, and exit velocity. Such information may be used to create performance databases for a variety of analytical and/or statistical evaluations. When used as an input into implement manufacturing, the results obtained from the system may also be used to maximize player safety, for example, by ensuring that exit velocity does not exceed a predetermined threshold.
The present invention provides methods and apparatus for testing striking-type sports implements. Although many of the descriptions contained herein relate to baseball batting, the system is equally applicable to sports which use rackets or mallets and projectiles other than round balls. Thus, the invention may be used to test and evaluate equipment associated with softball, tennis, squash, badminton, and other sports.
Broadly, a testing process according to the invention comprises the steps of mechanically swinging the striking implement along a predetermined swing path while delivering the ball or other appropriate projectile along a predetermined delivery path and into the swing path such that it is struck and enters a flight path. As this occurs, one or more of the following are measured: the swing speed of the implement, the delivery speed of the projectile and the exit velocity of the projectile. Preferably the swing speed of the implement and the delivery speed of the projectile are measured near a point proximate to the point of striking contact, whereas exit velocity is preferably measured at a plurality of points along the flight path, not only to determine speed, but also to determine and use angular displacement along the trajectory for a more accurate reading. Based upon these measurements, a programmed computer is used to develop, compile and/or display performance characteristics, such as the ability of different implements to produce a given exit velocity as a function of projectile type, delivery speed, swing speed, and so forth.
With specific regard to baseball, a hardware embodiment of a batting machine according to the invention includes a bat-swinging module, a ball-delivery module, and one or more programmed computers. Preferably, a main computer is used for data acquisition and analysis purposes as discussed above, with a second computer being dedicated to bat-swing and ball-delivery module control, thereby off-loading the main computer of tasks associated with bat and ball timing, speed and contact-point coordination.
A bat-swinging module according to the invention includes means to grip a bat at its handle end, and an electromotive source to swing the bat. A ball-delivery module may include a ball support and a different electromotive source operative to place the ball into the swing of the bat along a delivery path, enabling the bat to strike the ball and cause the ball to travel along a trajectory path. The electromotive sources are preferably implemented as computer-controlled servo motors, with the second computer being used to develop and deliver appropriate control signals to the motors to effectuate a highly accurate and predictable interaction between the bat and ball and a consistent flight path.
In a preferred arrangement, the ball delivery module includes a swing arm terminating in a fork with upper and lower members between which the ball is supported. The use of a fork shape enables the bat to swing between the upper and lower members while accurately adjusting the contact point. The ball support itself may either includes means for actively releasing the ball immediately prior to contact through the use of computer-controlled solenoid release switches. Alternatively, a break-away structure may be used which automatically releases the ball when struck. Different structures of this type are disclosed, including a two-piece arrangement having upper and lower cradles, and a one-piece unit having a central aperture within which the ball is carried. In preferred embodiments, these break-away structures are composed primarily of lightweight foam to minimize their impact on the various measurements.
A bat-swing sensor is used to output a signal carrying information associated with the swing speed of the bat. A ball-delivery speed sensor, disposed along the delivery path, is used to output a signal carrying information relating to the velocity of the ball, that is the xe2x80x9cpitchxe2x80x9d speed. In the preferred embodiment, a plurality of sensors are used to accurately determine exit velocity, with a first set of sensors being used to determine initial exit velocity as a function of angular displacement.
In response to an operator input, the main computer activates a hitting sequence mediated by the second computer while monitoring the signals output by the various sensors for data acquisition and analysis purposes. By selecting the sensed values indicative of the highest exit velocity, the system is able to automatically obtain accurate measurements despite slightly curved or angled trajectories, whatever the reason for such departures from a xe2x80x98perfectxe2x80x99 flight path.
The automated batting machinery and methods just described may be used in conjunction with a swing tester and an automated manufacturing process, both of which are also described herein. In the case of the swing tester, a human player is used to test a particular implement. For example, regard to baseball, a ball is positioned on a vertical, nonrigid support, with sensors on either side being used to measure bat swing and ball speed to determine a range of potential performance criteria, which may then be fed into the hitting machine for a much more refined analysis, including the ability to set more appropriate swing speeds.
In terms of automated manufacturing, as the performance characteristics are developed according to the invention, the information derived may be fed into a forming process to create an implement with specific performance range or restrictions. For example, in the case of a baseball bat, with knowledge of certain physical characteristics of the starting blank or xe2x80x9cbillet,xe2x80x9d such as material composition, size, weight, center of gravity, density, and so forth, the information obtained from the hitting machine may be input to an automated lathe or other automatically controlled formation apparatus to create a bat exhibiting a particular performance aspect or range of behavioral attributes. This input to automated manufacturing is also applicable to non-wooden, composite, and metal implements, including aluminum bats, graphite rackets, and so forth.
The combination of the swing tester, which may be used to determine a particular range of performance capabilities, the hitting machine, which may be used to analyze a highly refined set of performance criteria, and the automated manufacturing processes may be used cooperatively to form a closed loop linking the capabilities of a human player to an end product having extremely exacting performance capabilities.